Gritty triggers usually fall under a few particular issues.
1. Factory failed to clean out the manufacturing shavings properly.
not unusual to find metal shavings in your trigger assembly area...
2. It was not properly fitted/polished at the factory.
(Friday afternoon runaway/Monday Morning Hangover pistol)
3. Prior owner/owners failed to clean it properly.
Literally can find almost ANYTHING in there...sand/grit/small bugs...
All are resolved by pulling it apart & inspecting...cleaning, polishing where needed,
lube, then reassemble.
What else are ya gonna do during the Super Bowl??
Got all that free time to play with my guns, ain't gonna waste it